Rubber gloves are used in a wide range of fields such as housework, food industry, electronics industry, and medical field. In the past, rubber gloves made by dip-molding of natural rubber latex were used, but the protein contained in natural rubber was problematic due to allergic reactions such as pain and rash to some users.
Because of this, many gloves made by dip-molding the latex composition in which sulfur and a vulcanization accelerator are mixed with a carbonic acid-modified nitrile-based copolymer latex such as an acrylic acid-acrylonitrile-butadiene copolymer latex, which does not cause an allergic reaction, were used.
The carbonic acid-modified nitrile-based copolymer latex has a certain ratio of acrylic acid, acrylonitrile and butadiene, that is, in the form of organic acid segments. In recent years, attempts have been made to add physical properties such as tensile strength and durability required as rubber gloves by adding a crosslinking agent to the latex.
For example, in WO 2011/068394, a method has been proposed in which acrylonitrile is carboxylated and a metal oxide such as zinc oxide or another metal salt is added thereto and crosslinked by ionic bonds therebetween. However, such crosslinking alone does not satisfy a sufficient level of tensile strength and durability, and a new problem occurs in that some metals remain in the final molded article, resulting in deterioration of physical properties and skin irritation.
Moreover, in order to increase productivity in the nitrile glove market, which is currently replacing natural rubber gloves, the goal is to manufacture thin, yet non-tearable gloves by raising the production line speed.
However, when the concentration of the latex composition is lowered to simply make the glove thin, there may be problems in workability when manufacturing gloves. Therefore, when the glove is manufactured, a technique for making a glove which is good in workability and has a high tensile strength and is not torn even when the thickness is thin is required.